Not applicable.
Not applicable.
1. Field of the Invention
The invention relates to a plastic pallet that passes the Underwriters Laboratory UL 2335 protocol for pallets wherein said pallet comprises at least one resin selected from the group consisting of:
(a) polyphenylene ether resin and blends containing polyphenylene ether resin,
(b) polycarbonate resin and blends containing polycarbonate resin,
(c) vinyl aromatic graft copolymers;
(d) polyetherimide resin and blends containing polyetherimide resin, and
(e) thermosetting resins.
In a preferred embodiment, the plastic pallet has an open deck design. In another preferred embodiment, the pallet comprises at least one resin that contains a flame retardant.
2. Brief Description of the Related Art
There are many types of plastic pallets which are widely being used throughout the world to facilitate shipment and transportation of goods. The purpose of the pallet is to provide a support for the cargo particularly during shipment and storage and there has been an increasing requirement for such pallets to become more sophisticated due to varying standards and demands.
Conventionally pallets have been formed of timber, however, these pallets have suffered several disadvantages due to the inherent characteristics of wood. Such wooden pallets are naturally heavy, bulky, and expensive because of the nature of the material used in their construction. In addition, wooden pallets suffer deterioration due to inclement weather conditions and can suffer damages as a result of water which may be present in the location in which they are being used. The presence of such water results in the rotting of the timber and resultant weakening of the structure of the pallet. Furthermore such pallets are generally held together by means of gluing using suitable adhesives and/or nails or staples which are formed of metal. These methods of fixing of the components of the pallets together can also suffer as a result of the inclement conditions the pallet is required to undergo as a result of deterioration of the adhesive and/or corrosion of the nails or staples. Furthermore such pallets can be the subject of insect infestation which can result in the deterioration of the pallet but also can result in the introduction of undesirable infestations of insects from one location to another.
With improved quality control the difficulties created by utilization of wooden pallets have rendered such pallets as being generally undesirable and has resulted in the need for pallets of a higher standard.
Plastic pallets have been proposed as an alternative to wooden pallets, however, such plastic pallets generally flow during fires spreading molten plastic and generating dangerously high levels of heat. Because of these increased risks, the use and storage of plastic pallets has been more stringently regulated by National Fire Protection Association (NFPA 231 and NFPA 231C) and Factory Mutual than wood pallets. The more stringent regulations for plastic pallets, both for commodity storage and idle pallet storage, has diminished their utility. For example, plastic pallets require a one level increase in the class level for commodity storage and must be stored either outside or in a detached structure for idle pallet storage.
Recent changes to NFPA 231 and NFPA 231C allow for plastic pallets to be regulated the same as wood pallets when experimental data show equivalency in the burning and suppression characteristics between the plastic and wood pallets and the pallets are listed for such equivalency. The changed protocols provide that specific test data will take precedence for determining classification of commodities. It is believed that prior to the present invention, no pallet made from a plastic composition has met this equivalency.
The needs discussed above have been generally satisfied by the discovery of plastic pallets that pass the Underwriters Laboratory UL 2335 protocol for pallets wherein said pallets comprise at least one resin selected from the group consisting of:
(a) polyphenylene ether resin and blends containing polyphenylene ether resin,
(b) polycarbonate resin and blends containing polycarbonate resin,
(c) vinyl aromatic graft copolymers;
(d) polyetherimide resin and blends containing polyetherimide resin, and
(e) thermosetting resins.
In a preferred embodiment, the plastic pallet has an open deck design. In another preferred embodiment, the pallet comprises at least one resin that contains a flame retardant.
The description which follows provides further details regarding this invention.
Not applicable.